Blood samples were collected from 6 different donors, spiked with tumor cells expressing tyrosinase, and stored for up to 10 days at room temperature. RT-PCR was used to measure levels of tyrosinase. [A] 1 cell per 2.5 ml blood; [B] 10 cells per 2.5 ml blood. WB: tyrosinase detection in RNA isolated from whole blood collected and stored in standard EDTA tubes. PAX: tyrosinase detection using the PAXgene Blood RNA System for sample collection, and RNA stabilization and isolation. (Data kindly provided by LMO, Munich, Germany.)

RNA isolation begins with a centrifugation step to pellet nucleic acids in the PAXgene Blood RNA Tube. The pellet is washed, and proteinase K is added to digest proteins. Alcohol is added to adjust binding conditions. Lysates are applied to the PAXgene 96 Filter Plate and centrifuged to remove cell debris. The lysate is then applied to a PAXgene 96 RNA Plate. Residual DNA is removed through a DNase I digestion. Remaining contaminants are removed in three efficient wash steps before pure RNA is eluted.